Heterocyclically substituted piperazinoakylbenzoxazine and piperazinoalkylbenzothiazine compounds, processes for preparing them, and medicaments containing them

ABSTRACT

Pharmacologically active compounds corresponding to the general formula I ##STR1## which are optionally substituted in the benzene ring and in which X denotes oxygen or sulfur, 
     Y denotes oxygen or sulfur, 
     R 1  denotes hydrogen or lower alkyl, 
     n is an integer from 0 to 4, and 
     R 4  is an optionally substituted 6-membered unsaturated heterocycle containing 1 or 2 nitrogen atoms not directly bonded to the piperazine ring, 
     and physiologically acceptable acid addition salts thereof.

This application is a continuation of application Ser. No. 07/792,395, filed Nov. 15, 1991 now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to novel benzoxazine-3-one and benzothiazine-3-one derivatives which carry in the 2-position a piperazinoalkyl group substituted by a heterocycle, and the corresponding 3-thione derivatives and salts thereof; to processes for preparing such compounds, and to pharmaceutical compositions containing such compounds.

1,4-Benzoxazine-3-one derivatives which carry a phenylpiperazinoalkyl group in the 2-position are known from published European patent application No. EP 233,728. These compounds have pronounced hypotensive and vasodilating effects.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide new pharmaceutically active compounds which can be used as anti-allergic agents.

Another object of the invention is to provide new benzoxazine derivatives having valuable pharmacological properties.

These and other objects of the invention are achieved by providing a compound corresponding to the formula I ##STR2## wherein X denotes oxygen or sulfur,

Y denotes oxygen or sulfur,

R¹ denotes hydrogen or lower alkyl,

R² denotes hydrogen, lower alkyl, halogen, lower alkoxy, hydroxy, nitro or trifluoromethyl, and

R³ denotes hydrogen, lower alkyl, halogen or lower alkoxy, or

R² and R³ are bonded to adjacent carbon atoms and together denote an alkylenedioxy group having 1-2 carbon atoms,

n is an integer from 0 to 4, and

R⁴ is a 6-membered unsaturated heterocycle containing 1 or 2 nitrogen atoms not directly bonded to the piperazine ring, said heterocycle being substituted by 0 to 2 substituents bonded to carbon atoms selected from the group consisting of lower alkyl, lower alkoxy and halogen,

and physiologically acceptable acid addition salts thereof.

According to a further aspect of the invention, the objects are achieved by providing a pharmaceutical composition comprising an effective anti-inflammatory or anti-allergic amount of a compound as described above and at least one conventional pharmaceutical adjuvant.

In accordance with another aspect of the invention, the objects are achieved by providing a process for preparing a compound corresponding to the formula I ##STR3## wherein X denotes oxygen or sulfur,

Y denotes oxygen or sulfur,

R¹ denotes hydrogen or lower alkyl,

R² denotes hydrogen, lower alkyl, halogen, lower alkoxy, hydroxy, nitro or trifluoromethyl, and

R³ denotes hydrogen, lower alkyl, halogen or lower alkoxy, or

R² and R³ are bonded to adjacent carbon atoms and together denote an alkylenedioxy group having 1-2 carbon atoms,

n is an integer from 0 to 4, and

R⁴ denotes a 6-membered unsaturated heterocycle containing 1 or 2 nitrogen atoms not directly bonded to the piperazine ring, said heterocycle being substituted by 0 to 2 substituents bonded to carbon atoms selected from the group consisting of lower alkyl, lower alkoxy and halogen,

and acid addition salts thereof, wherein said process comprises:

a) to prepare a compound corresponding to the formula Ia ##STR4## wherein X, R¹, R², R³, n and R⁴ have the above meanings, reacting a compound corresponding to the formula II ##STR5## wherein X, R¹, R³ and n have the above meanings,

R^(2') has the meaning given for R² except that any hydroxy group is protected by a subsequently removable protective group, and

L denotes an aminolytically cleavable radical,

with a piperazine derivative corresponding to the formula III ##STR6## wherein R⁴ has the above meaning, or

b) reacting a compound corresponding to the formula IV ##STR7## wherein X, R¹, ^(2'), R³ and n have the above meanings, with a compound corresponding to the formula V

    R.sup.4 --L'

wherein R⁴ has the above meaning and L' denotes halogen, and then removing any hydroxy protective group, or

c) converting a compound corresponding to the formula Ia to a compound corresponding to the formula Ib ##STR8## wherein X, R¹, R², R³, n and R⁴ have the above meanings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The novel heterocyclically substituted compounds of the invention have been found to have valuable pharmacological properties, to show anti-inflammatory and anti-allergic effects, and to have an advantageous activity profile with low toxicity and good tolerance. Due to their activity profile, the compounds of the invention are suitable for use as anti-inflammatory active ingredients and anti-allergic agents in the treatment of inflammatory and allergic diseases.

The present invention therefore relates to novel compounds of the general formula I ##STR9## wherein X denotes oxygen or sulfur,

Y denotes oxygen or sulfur,

R¹ denotes hydrogen or lower alkyl,

R² denotes hydrogen, lower alkyl, halogen, lower alkoxy, hydroxy, nitro or trifluoromethyl, and

R³ denotes hydrogen, lower alkyl, halogen or lower alkoxy, or

R² and R³ are bonded to adjacent carbon atoms and together denote an alkylenedioxy group with 1-2 carbon atoms,

n is an integer from 0 to 4, and

R⁴ is a 6-membered unsaturated heterocycle containing 1 or 2 nitrogen atoms not directly bonded to the piperazine ring, which heterocycle may optionally be substituted by 1-2 substituents bonded to carbon atoms and selected from the group consisting of lower alkyl, lower alkoxy and halogen,

and physiologically acceptable acid addition salts thereof.

In so far as the substituents R² and R³ in the compounds of formula I and the substituents in the group R⁴ represent or contain lower alkyl groups, these may be straight or branched and contain in particular 1-4, preferably 1-2, carbon atoms and represent in particular methyl or methoxy. In so far as the substituents represent halogen, they may be fluorine, chlorine or bromine, preferably chlorine. The benzene ring of the ring structure may advantageously be unsubstituted. In so far as the benzene ring is substituted by a substituent R², or by two substituents R² and R³, lower alkyl substituents, for example methyl substituents, are considered especially suitable.

The substituent R¹ advantageously represents hydrogen. If R¹ represents lower alkyl, it may be straight-chain or branched and may contain 1-4, in particular 1-2, carbon atoms.

In the compounds of the formula I, n represents 0-4. An alkylene chain having 3 or 4 members has proved to be particularly advantageous.

The substituent R⁴ may represent an unsaturated heterocycle containing one or two nitrogen atoms, for example a heteroaryl group. Suitable R⁴ groups include, for example, pyridyl, pyrimidinyl, pyrazinyl or pyridazinyl residues, particularly pyridyl groups. If R⁴ represents a pyridyl group, it is preferred to use a pyrid-2-yl group, which optionally may be substituted. For example, unsubstituted pyridyl radicals or pyridyl radicals which are substituted by lower alkyl, in particular methyl, are suitable. A 4-methylpyrid-2-yl group is particularly advantageous.

In accordance with the invention, the novel compounds of formula I and their acid addition salts are obtained in a known manner by

a) to prepare compounds of the general formula Ia ##STR10## in which X, R¹, R², R³, n and R⁴ have the above meanings, compounds of the general formula II ##STR11## in which X, R¹, R³ and n have the above meanings, and R^(2') has the meaning given for R², but wherein a hydroxy group is protected by a subsequently removable protective group, and L is an aminolytically clearable residue, especially halogen,

are reacted with piperazine derivatives of the general formula III ##STR12## in which R⁴ has the above meaning, or

b) compounds of the general formula IV ##STR13## in which X, R¹, R^(2'), R³ and n have the above meanings, are reacted with compounds of the general formula V

    R.sup.4 --L'

in which R⁴ has the above meaning and L' denotes halogen, and any hydroxy protective group is subsequently removed, or

c) compounds of the general formula Ia are converted to compounds of the general formula Ib ##STR14## in which X, R¹, R², R³, n and R⁴ have the above meanings, and optionally compounds of the general formula I which are obtained in which R¹ represents hydrogen, are alkylated to form compounds of the general formula I in which R¹ represents lower alkyl, and/or in compounds of the general formula I which are obtained in which R² represents methoxy, the methoxy group is cleaved to form a hydroxy group, and optionally free compounds of the formula I are converted to their acid addition salts or the acid addition salts are converted to the corresponding free compounds of formula I.

The reaction of compounds of formula II with compounds of formula III according to process variant a) may be carried out by conventional methods for alkylating amines.

The reaction is advantageously carried out under basic conditions in an organic solvent which is inert under the reaction conditions.

Halogens, such as chlorine, bromine or iodine, preferably bromine or chlorine, or also an acyloxy radical O--Z, in which Z represents a lower alkanoyl group or an organic sulfonic acid group, for example the radical of a lower alkanesulfonic acid such as, for example, methane sulfonic acid, or of an aromatic sulfonic acid such as benzenesulfonic acid or benzenesulfonic acids substituted by lower alkyl or by halogen, for example toluenesulfonic acids or bromobenzenesulfonic acids, are suitable as aminolytically cleavable residues L in the compounds of formula II.

Aprotic solvents in particular, for example aromatic hydrocarbons such as toluene, xylene or benzene; cyclic ethers such as dioxane; dimethylformamide; or lower alkanols such as ethanol; or mixtures of the foregoing solvents are suitable as inert organic solvents.

The process is advantageously carried out at elevated temperatures, for example temperatures between 50° and 150° C., preferably at the reflux temperature of the solvent.

The reaction is advantageously carried out with addition of an organic or inorganic base. However, an excess of the compound of the formula III may also be used, and this may serve as an internal base. Examples of suitable organic bases include tertiary organic amines, in particular tertiary lower alkyl amines such as triethylamine or tripropylamine, N-lower alkyl morpholines or N-lower alkyl piperidines. Suitable inorganic bases include in particular alkali metal carbonates or bicarbonates.

The reaction time may be between 2 and 8 hours depending on the reaction conditions.

Known ether protective groups, which can subsequently be removed solvolytically or hydrogenolytically in a known manner, for example lower alkyl or benzyl groups, may be selected as protective groups for any hydroxy group R² which may be present.

The reaction of compounds of formula IV with compounds of formula V according to process variant b) may be carried out by conventional methods for alkylating amines. For example, it may be carried out in the manner described for reacting compounds of formula II with compounds of formula III.

The conversion of the 3-one group of the compounds of formula Ia into the 3-thione group of the compounds of formula Ib according to process variant c) may be carried out by conventional methods for exchanging oxygen for sulfur in oxo compounds. Thus the compounds of formula Ib may be prepared in a known manner, for example by treating the compounds of formula Ia with a phosphorus pentasulfide (for example P₄ S₁₀) or also according to the method described by Lawesson et al. (see Bull. Soc. Chim. Belg. 87, 525-534 (1978)) by reacting with 2,4-bis(methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide of the formula VI ##STR15## (=known as Lawesson's reagent). The deoxosulfurization is advantageously carried out in an organic solvent which is inert under the reaction conditions, for example an aromatic hydrocarbon such as xylene or toluene, at elevated temperatures, for example temperatures between 50° and 150° C., advantageously at the reflux temperature of the reaction mixture. When the reaction is completed, the sulfurized compounds may be separated by filtration from the phosphorus derivatives.

If desired, compounds of formula I which are obtained in which R¹ represents hydrogen may be subsequently alkylated in a known manner to form the corresponding N-alkyl compounds. Suitable alkylating agents include alkyl halides, particularly iodides, alkyl sulfates or alkyl sulfonates. A compound of formula I containing an amide or thiamide group is advantageously reacted initially with a strong base, such as for example an alkali metal hydride, alkali metal amide or alkali metal alcoholate, in an inert polar organic solvent and then further reacted with the alkylating agent. The reaction may be carried out at a temperature of 0° C. up to the reflux temperature of the solvent. Dimethylformamide or cyclic ethers, such as tetrahydrofuran or dioxane, are suitable as solvents depending on the base used, or, if the base is a metal alcoholate, also the corresponding alcohols. Thus, for example, the reaction may advantageously be carried out in dimethylformamide using sodium hydride.

In compounds of formula I in which R² denotes methoxy, the methoxy group may be cleaved to form the hydroxy group in a known manner using methods suitable for cleaving methoxyaryl ethers. For example, the ether may be cleaved by treating with hydrogen iodide in a solvent which is inert under the reaction conditions, for example acetanhydride, or with iodotrimethylsilane or boron tribromide.

The compounds of the formula I may be isolated from the reaction mixture and purified in a known manner. Acid addition salts may be converted to the free bases in a conventional manner, and if desired, the free bases may be converted in a known manner to pharmacologically acceptable acid addition salts.

Suitable pharmacologically acceptable acid addition salts of the compounds of formula I include, for example their salts with inorganic acids, for example hydrohalic acids, particularly hydrochloric acid, sulfuric acid or phosphoric acids, or with organic acids, for example lower aliphatic monocarboxylic or dicarboxylic acids, such as maleic acid, fumaric acid, lactic acid, tartaric acid or acetic acid, or sulfonic acids, for example lower alkyl sulfonic acids such as methanesulfonic acid, or benzenesulfonic acids optionally substituted in the benzene ring by halogen or lower alkyl, such as p-toluenesulfonic acid, or cyclohexylaminesulfonic acid.

The compounds of the formula I contain an asymmetric center in the 2-position of the benzoxazine or benzothiazine structure and may exist in two optically active enantiomeric forms or as a racemate. The present invention includes both the racemic mixtures as well as the pure optical isomers of the compounds of formula I.

If racemates of compounds of formula II or formula IV are used in the synthesis, the resulting compounds of formula I are obtained in the form of racemates. Optically active compounds corresponding to formula I may be obtained starting from optically active forms of compounds of formula II or formula IV. Optically active compounds of formula I may be isolated from racemic mixtures in a known manner, for example by chromatographic separation on chiral separating materials or by reacting with suitable optically active acids, for example tartaric acid or 10-camphorsulfonic acid, and then separating the resulting salts into their optically active antipodes by fractional crystallization.

The starting compounds of formula II may be obtained starting from 2-aminophenol derivatives corresponding to the formula VII ##STR16## in which R¹, R^(2'), R³ and X have the above meanings. Accordingly, the compounds of formula VII may be condensed in a known manner with a β-bromo-acylbromide of formula VIII ##STR17## in which L has the above meaning, and n' denotes 1-4, to form compounds of the formula IIa ##STR18## in which R¹, R^(2'), R³, X, n' and L have the above meanings. The condensation may be carried out in a solvent which is inert under the reaction conditions, for example a halogenated hydrocarbon such as chloroform, in the presence of a base, for example an alkali metal hydrogen carbonate or alkali metal carbonate, and is advantageously carried out in the presence of a transfer catalyst, for example benzyltrimethylammonium chloride. The compounds of the formula VII can also be reacted in a known manner with methyl β-bromo-alkanecarboxylates of the formula IX ##STR19## in which n' and L have the above meanings, to form compounds of the formula IIa. The reaction may, for example, be carried out in dimethylformamide in the presence of an inorganic base, for example an alkali metal carbonate.

Compounds of the general formula VIIa ##STR20## in which R¹, R^(2') and R³ have the above meanings, are known or may be obtained in a known manner starting from compounds of the general formula XIII ##STR21## in which R^(2') and R³ have the above meanings. Compounds of the formula XIII may be alkylated to introduce an alkyl radical R¹ in a known manner to form compounds of the general formula XIV ##STR22## in which R^(2') and R³ have the above meanings, and R^(1') denotes lower alkyl.

Compounds of formula XIII or formula XIV may be converted to compounds of formula VIIa in a known manner by thermal dissociation in an aqueous alkaline medium, for example by heating in alkali metal hydroxide solution.

Compounds of the general formula VIIb ##STR23## in which R¹, R^(2') and R³ have the above meanings, are known or may be obtained by known methods or analogously to known methods. 2-Alkylaminophenol compounds (R¹ =lower alkyl) may be obtained starting from the corresponding 2-aminophenol compounds. For this purpose they are initially acylated, whereby both the phenolic hydroxy group and the amino group are provided with a protective acyl group. The amide group in the resulting ester-amide compounds is alkylated in a known manner by reacting the compounds with an alkylating agent, for example a lower alkyl halide, alkyl sulfate or alkyl sulfonate, in the presence of a strong base, for example an alkali metal hydride or alkali metal hydroxide, optionally in the presence of a transfer catalyst, for example benzyltrimethylammonium chloride. The reaction may take place, for example under the conditions given above for the subsequent alkylation of compounds of the formula I. After the alkylation is completed, the protective acyl groups may then be removed in a known manner by acid or alkaline hydrolysis.

Compounds of formula II in which n denotes 0, may be obtained starting from compounds of the formula X ##STR24## in which R¹, R^(2'), R³ and X have the above meanings. Hence, to prepare compounds of the formula IIb ##STR25## in which R¹, R^(2') and R³ have the above meanings, and L' denotes halogen. A halogen substituent L', particularly chlorine, can be introduced into compounds of the formula X in a known manner by treatment with a halogenating agent, for example sulfuryl chloride. The chlorination may be carried out in a solvent which is inert under the reaction conditions, for example a halogenated hydrocarbon such as dichloromethane.

Compounds of formula X are known or may be obtained in a known manner, for example by condensing compounds of formula VII with chloroacetyl chloride. The condensation may be carried out under the reaction conditions given above for preparing compounds of formula IIa.

Compounds of the formula IV have not previously been described in the literature and constitute novel, valuable intermediate products for synthesizing pharmacologically active compounds, for example the compounds of formula I.

Compounds of the formula IV may be obtained according to known methods by reacting, for example, compounds of formula II with an excess of piperazine. The reaction may be carried out following conventional methods for alkylating amines, for example under the conditions described above for reacting compounds of the formula II with compounds of the formula III.

Compounds of the formula IV may also be obtained from compounds of the general formula XI ##STR26## in which R¹, R^(2'), R³ and X have the above meanings, and Q denotes an amine protective group, by removing the amine protective group in a known manner. Suitable amine protective groups include the usual protective groups used for protecting an amino function, for example hydrolytically removable acyl groups or hydrogenolytically removable benzyl groups. Suitable protective groups are known, for example from E. McOmie, "Protective Groups in Organic Chemistry"; Plenum Press, London (1971), page 44 ff. The formyl group and lower carbalkoxy protective groups are particularly suitable. They may be removed in a known manner by acid or alkaline hydrolysis.

Compounds of the formula XI may be obtained in a known manner, for example by reacting compounds of the formula II with compounds of the formula XII ##STR27## in which Q has the above meaning. The reaction may be carried out following conventional methods for alkylating amines, for example under the reaction conditions described for the reaction of compounds of formula II with compounds of formula III.

Compounds of the formula III are known or may be prepared following known methods, for example by reacting compounds of formula V with an excess of piperazine or with a compound of formula XII and subsequently removing the protective group Q.

The compounds of formula I and their pharmacologically acceptable acid addition salts are characterized by interesting pharmacological properties and have anti-inflammatory and anti-allergic effects. In particular, the compounds exhibit an advantageous activity profile for treating asthmatic disorders with low toxicity and good compatibility.

Asthma is a chronic inflammatory lung disease which is characterized by an episodic, reversible obstruction of the respiratory passages. It is generally assumed that the initiation of asthmatic symptoms and attacks stems from a parenchymal and interstitial cell type known as a mast cell. These mast cells contain pre-formed inflammation mediators and spasmogens, in particular histamine. They are also capable of synthesizing a variety of mediators derived from membrane lipids. Mast cells also act in conjunction with a number of associated cells which are all capable of synthesizing inflammatory and pro-inflammatory mediators.

As long as no allergy-inducing conditions are present, the mast cells are in a quasi dormant waiting state. The key to allergic reactions lies in the presence of high concentrations of circulating IgE antibodies. When these antibodies bind to a corresponding antigen, they activate both the degranulation and release of pre-formed mediators as well as the synthesis of other mediators.

Since asthma is an inflammatory obstructive lung disease, the therapy is based on essentially two approaches: alleviating the symptomatic complaints by administering bronchodilators such as β-sympathicomimetic agents, xanthine derivatives and anti-cholinergic agents; administration of anti-inflammatory active ingredients such as disodium cromoglycinate and steroids; and targeted therapy directed at specific mediators such as histamine, for example. Treatment to alleviate the symptomatic complaints is adequate in about 50% of asthmatics, but does not contribute anything to alleviating the cause, i.e. the inflammation. Anti-inflammatory active ingredients may control the inflammation, but often have undesirable side-effects and are frequently administered simultaneously with bronchodilators. Targeted therapy directed at a specific mediator alone is totally inadequate, since there are plethora of mediators.

The compounds of the invention are distinguished in that they have an anti-inflammatory effect and act in targeted fashion against one or more of the three types of mediators: histamine, leucotrienes and blood platelet aggregating factor, which contribute not only to acute bronchospasms but also to maintenance of chronic inflammation, or are also active against the respective target cells via mediator-specific receptors.

The anti-inflammatory and anti-allergic properties of the compounds of the invention can be demonstrated in vitro and in vivo by standard pharmacological test methods.

DESCRIPTION OF THE TEST METHODS 1. Determining Inhibition of Passive Cutaneous Anaphylaxis (PCA) and Histamine-Induced Anaphylactoid Cutaneous Reaction

The PCA reaction is carried out following the methods described by Goose et al. (J. N. Immunology 16 (1969), 749) and by Martin et al. (Arch. Pharmacol. 316 (1981), 186).

The IgE-rich ovalbumin antiserum used in the test was obtained from immunized Brown-Norway rats. The were immunized with an intraperitoneal injection of a mixture of 100 μg of ovalbumin with a Bordetella pertussis suspension (Vaxicoq™, Manufactured by Institute Merieux, containing 5×10⁹ organisms and 1.25 mg Al(OH)₃). After 20 days the animals were re-immunized with a further intraperitoneal injection of a solution of 10 μg ovalbumin in 0.5 ml physiological saline solution. After a further four days the blood was removed from the animals and centrifuged. The resulting antiserum was stored at -20° C. until use.

The inhibition of the passive cutaneous anaphylaxis and of the anaphylactoid cutaneous reaction induced by histamine was determined as follows:

Sprague-Dawley rats having a body weight of 150-180 g were injected intradermally in one flank with 50 μl of a 1:75 dilution of the IgE-rich ovalbumin antiserum in physiological saline solution to passively sensitize them to ovalbumin.

24 hours after sensitization a solution of 8.25 mg/kg of ovalbumin and 26.4 mg/kg of a blue dye (Evans's Blue) was administered to the rats intravenously according to Martin et al. to trigger passive cutaneous anaphylaxis. The ovalbumin challenge resulted in a local anaphylactic reaction at the point where the antiserum was injected.

To determine the histamine-induced anaphylactoid skin reaction, the animals are injected intradermally in the flank opposite to the antiserum administration with 50 μl of a physiological saline solution containing 0.8 mg/ml histamine directly before the intravenous injection of the solution containing the ovalbumin and the blue dye.

On the day of the experiment the test substances were dissolved in distilled water which contained 1 vol. % dimethylformamide and 1 vol. % of Tween™ 20 (=polyoxyethylene (20) sorbitan monolaurate). One hour before administration of the ovalbumin challenge, each animal was orally administered 2×10⁻⁵ mole/kg of test substance in 0.5 ml of solution. For comparison purposes a control group received only the solvent.

The edematous anaphylactic (PCA) and anaphylactoid (histamine-induced) reactions caused by the stimulation of the intravenous ovalbumin injection, which manifested themselves by edema formation, swelling and exudation of blue dye, were evaluated 30 minutes after their initiation by the intravenous ovalbumin injection. This was done by visually determining the extent to which the blue dye emerged at the sites of edema formation. The percentage inhibition of anaphylactic and anaphylactoid reactions induced by the test substances in comparison with the reactions of the control animals not treated with any test substance was determined using comparison scales.

The results obtained using compounds of formula I according to the foregoing test methods are shown in the following Table A. The example numbers given for the compounds of formula I relate to the subsequent preparative examples.

                  TABLE A                                                          ______________________________________                                                   Inhibiting effect on cutaneous anaphylactic                          Test      and anaphylactoid reactions in Rats                                  Substance % inhibition by 2 × 10.sup.-5 mole/kg dose per os              Example   Passive cutaneous                                                                              Histamine-induced                                    No.       anaphylaxis (PCA)                                                                              anaphylactoid reaction                               ______________________________________                                         22        69              45                                                    7        70              40                                                    9        60              30                                                    1        88              55                                                    8        73              60                                                   12        80              50                                                   13        55              30                                                   15        60              30                                                   16        50              45                                                   17        70              35                                                   11        55              20                                                   10        70              35                                                    3        80              55                                                   18        80              53                                                   19        80              60                                                   21        78              55                                                   24        80              60                                                   25        50              15                                                   27        60              35                                                   28        65              40                                                   ______________________________________                                    

2. Determination of Minimum Toxic Dose

Maximum doses of 300 mg/kg of the test substance were administered orally to male mice weighing 20-25 g. The animals were observed carefully for 3 hours for toxicity symptoms. In addition, all symptoms and deaths were recorded over a period of 24 hours after administration. Associated symptoms were also observed and recorded. If death or severe toxic symptoms were observed, additional mice were administered increasingly lower doses. The lowest dose which produced death or severe toxic symptoms is given in the following Table B as the minimum toxic dose.

                  TABLE B                                                          ______________________________________                                         Test Substance                                                                             Minimum toxic dose mg/kg mouse                                     Example No. per os                                                             ______________________________________                                          1          300                                                                22          300                                                                 8          100                                                                 9          300                                                                 2          >300                                                               11          >300                                                               12          300                                                                13          100                                                                16          300                                                                ______________________________________                                    

3. Investigation of Anti-Histamine-(H₁) Effect Based on Histamine-(H₁)-Receptor Antagonism In Vitro

To investigate the histamine-(H₁)-receptor antagonism of the test substances, the inhibiting effect of the substances on histamine-induced contractions of the smooth muscle was determined in vitro on the isolated organ. Isolated strips of organ from the ileum are suitable for this purpose. In an organ bath of physiological saline solution the smooth muscle strips react to the addition of histamine by contracting. Addition of the compounds of the invention decreased the histamine-induced contraction of the smooth muscle of the ileum strips. The extent of regression of the contraction is an indication of the anti-histamine-(H₁) activity of the compounds. The investigation was carried out analogously to the method originally described by Magnus (Pfluegers Arch. 102, 123 (1904)).

Procedure for determining the smooth muscle contraction inhibiting effect on isolated guinea pig ileum induced by a 5×10⁻⁶ molar histamine concentration

Segments of the ileum 1.5 cm long from Dunkin Hartley guinea pigs having a body weight of 300 500 g were used for the test. Each strip was placed in an organ bath of 10 ml of physiological saline solution according to Krebs-Henseleit and attached to a conventional apparatus for isotonic measurement of changes in length of the ileum strips (automated Celaster measuring apparatus), so that the tissue was under 1 g of tension. The bath was kept at a pH of 7.4 and gassed with a mixture of 5% CO₂ and 95% O₂. After an equilibration phase, an isotonic contraction of the tissue was induced by adding histamine in a final concentration of 5×10⁻⁶ mole/liter and washing it out again after a contact time of 30 seconds. Only tissues samples from which three reproducible contractions were obtained at 10 minute intervals were used in the subsequent test. The test substances were then added in a final concentration of 10⁻⁶ mole/liter, and after 30 seconds contact time histamine was again added up to a concentration of 5×10⁻⁶ mole/liter. The resulting contractions were measured over 30 seconds. The tissue was then washed several times over a period of 10 minutes. Histamine was then added again to stimulate a contraction. The resulting contractions were again measured over 30 seconds. The difference between the amplitude of the contraction obtained by histamine addition alone and the amplitude of the contraction obtained in the presence of the test substance was determined and expressed in terms of % inhibition.

The following Table C shows the results obtained with the test substances according to the method described above. The inhibiting effects on the contractions induced by histamine 30 seconds after administration of the test substance and on the contractions induced by the addition of histamine 10 minutes later are listed in the table.

                  TABLE C                                                          ______________________________________                                                      in vitro (H.sub.1)-receptor antagonism,                                        % inhibition of histamine-induced                                              ileum contractions at a histamine                                 Test         concentration of 5 × 10.sup.-6 mole/l                       Substance    and a test substance concentration                                Example      of 10.sup.-6 mole/l                                               No.          after 30 seconds                                                                           after 10 minutes                                      ______________________________________                                          7           85          74                                                     8           42           5                                                    13           42          15                                                    16           30          27                                                    11           32          35                                                     2           51          60                                                    10           42          36                                                     3           66          28                                                    18           78          83                                                    19           60          42                                                    21           50          89                                                    23           70          83                                                    24           70          86                                                    25           50          32                                                    27           16          72                                                    28           38          45                                                    ______________________________________                                    

4. Determination of Anti-PAF Activity In Vitro

PAF (=Platelet Activating Factor) is a phospholipid mediator which has many effects. Activation of platelet aggregation induces protracted broncho-contraction and hyper-reactivity of the air paths.

In this test the effect of the test substances on platelet aggregation induced by adding PAF to a suspension of platelets obtained from rabbit blood is investigated using the method described by Mikashima et al. (Jap. J. Pharmacol. 44 (1987) 387-391).

A suspension of platelets obtained from rabbit blood containing 4×10⁹ platelets/ml in a modified Tyrode buffer solution (=Tyrode solution with 1.3 mM/l CaCl₂ and 2.5 g/l gelatine added) adjusted to pH 7.4 was used. Tyrode solution is an aqueous solution containing 136.9 mmoles NaCl, 2.68 mmoles KCl, 2.31 mmoles CaCl₂, 1.0 mmole MgCl₂, 11.9 mmoles NaHCO₃, 1.45 mmoles NaH₂ PO₄ and 5.55 mmoles glucose per liter. The platelets were obtained from 10 ml blood samples from each of three rabbits (New Zealand hybrids, body weight 3-4 kg). For this the blood samples were treated with ethylenediamine tetraacetic acid and washed according to the method of Artley et al. (Brit. J. Hematol. 19 (1970), 7-17). A platelet-rich plasma was then initially separated by centrifuging (20 minutes at 400×g). The blood platelets were separated from the plasma by recentrifuging for 15 minutes at 1,400×g. The platelets remaining as sediment after centrifuging were resuspended in a Tyrode buffer solution (but without calcium). 0.4 mmole of lysine acetylsalicylate was then added, and after 15 minutes the platelets were sedimented again. The sediment was resuspended in the aforementioned modified Tyrode buffer solution, and the number of platelets in the resulting suspension was adjusted to the desired content.

A 40×10⁻⁹ molar PAF solution was used as a reagent. This solution was made from a 1.8×10⁻³ molar stock solution in chloroform. For this purpose a 10 μl sample of the stock solution was evaporated to dryness and redissolved in 180 μl of the modified Tyrode solution to which 0.25% of lipid-free bovine serum albumin had been added. From this 10⁻⁵ molar working solutions were then prepared and stored frozen. Samples of these solutions were appropriately diluted for the tests.

To carry out the test 50 μl of the platelet suspension and 10 μl of a 40×10⁻⁵ molar solution of the compound being investigated were added with stirring (1,000 rpm) to 330 μl of the modified Tyrode buffer solution in an aggregation tube provided with a small magnetic stirrer. This corresponds to a final test substance concentration of 10⁻⁵ mole/l. After 90 seconds preincubation time, 10 μl of the PAF preparation were added. The aggregation occurring in the aggregation tubes was measured over 4-5 minutes with the aid of a computerized aggregometer.

The aggregation which occurred in test tubes containing only platelet suspension was evaluated as 0%, whereas the aggregation which occurred in test tubes containing platelet suspension and PAF preparation was evaluated as 100%. The aggregation which still occurred during the inhibition of the PAF induced platelet aggregation due to the addition of the test substances was measured, and the resulting aggregation inhibition was calculated therefrom in %.

The results obtained using the compounds of formula I according to the foregoing method are shown in the following Table D.

                  TABLE D                                                          ______________________________________                                         Test    Anti-PAF activity in vitro                                             Substance                                                                              % inhibition of the PAF-induced aggregation                            Example of rabbit blood platelets at a test                                    No.     substance concentration of 10.sup.-5 mole/l                            ______________________________________                                         22      42                                                                      9      51                                                                      8      48                                                                     11      96                                                                      2      60                                                                     18      76                                                                     21      37                                                                     10      74                                                                     27      35                                                                     28      45                                                                     ______________________________________                                    

5. In Vitro Determination of Cyclooxygenase Inhibition And 5-lipoxygenase Inhibition.

After a cell is activated, arachidonic acid contained in cell membranes is metabolized in two ways. Leucotrienes, inter alia leucotriene C₄, are formed due to the action of the enzyme 5-lipoxygenase (=5-LO), and prostanoids are formed due to the action of the enzyme cyclooxygenase (=CO). In in vitro systems these metabolites are secreted from the cell.

To evaluate the cyclooxygenase-inhibiting and 5-lipoxygenase-inhibiting properties of the test substances, their inhibitory activity on the biosynthesis of the arachidonic acid derivatives leucotriene C₄ (=LTC₄) and 6-keto-prostaglandin F₁α (=6-keto-PGF₁α) was determined in vitro on mouse peritoneal macrophage cells. For this purpose the LTC₄ and 6-keto-PGF₁α contents of a mouse peritoneal macrophage cell culture medium were determined by zymosan stimulation as described by Scott et al. (J. Exp. Med. 152 (1980), 324-335) and by Fradin et al., (Prostaglandins, 33 (1987), 579-589).

A cell suspension containing peritoneal cells from male mice 8-10 weeks old was obtained in a known manner. A solution marketed under the designation RPMI 1640 (Manufactured by Gibco) was used as the cell culture medium, to which heparin (10 international units/ml) and antibiotics were added according to the procedure of Bonney et al. (Biochem. J. 176 (1978) 422-433). The cell suspension was adjusted to a cell concentration of 10⁶ cells per ml and distributed uniformly on titer dishes containing 24 1-ml titer cells (wells). These were kept for two hours in a humidified incubator filled with air enriched with 7% CO₂. Cells not adhering to the titer well walls were then removed by washing. The remaining macrophage cells adhering to the walls were incubated for about 12 hours in a suspension medium to which 0.1% of bovine serum albumin (BSA=Bovine Serum Albumin) was added. The suspension medium was then replaced by a Hanks salt solution (=Hanks Balanced Salt Solution=HBSS) with 10 mmoles of HEPES (=hydroxyethylpiperazinoethanesulfonic acid) to which a 0.1% strength solution of the test substances in aqueous, 1% strength dimethylformamide or only the solvent had been added. After 15 minutes the arachidonic acid metabolism was stimulated by adding 10 particles of zymosan (=glycoprotein mixture isolated from cell walls of beer yeast, Saccharomyces cerevisiae, Manufactured by Sigma Chemical Co., Munich) per titre cell. After 2 hours samples of the respective supernatant liquid in each cell were examined for their 6-keto-PGF₁α and LTC₄ contents by an enzyme immunoassay (=EIA). This EIA is carried out following the method of Pradelles et al. (Analytical Chem. 57 (1985), 1170-1173). The determination of LTC₄ and the determination of 6-keto-PGF₁α were each carried out on suitable dilutions of the samples (1:50 to 1:250 for the LTC₄ determination and 1:250 to 1:1,250 for the 6-keto-PGF₁α determination) in comparison with a comparative scale. To determine the inhibiting effect of a 10⁻⁵ molar concentration of the compounds, the amounts of reference eicosanoid were determined, and the inhibiting effect was calculated therefrom in % inhibition compared to the measurements of the zymosan controls. The results obtained in this test are shown in the following Table E.

                  TABLE E                                                          ______________________________________                                                        In vitro % inhibition in                                                       zymosan-stimulated mouse                                        Test           peritoneal macrophage                                           Substance      cells at a concentration of                                     Example         10.sup.-5 mole/l upon release of                               No.            6-keto-PGF.sub.1α                                                                   LTC.sub.4                                            ______________________________________                                         7              17         46                                                   9              32         65                                                   1              27         48                                                   5              36         72                                                   15             46          9                                                   11              0         42                                                   ______________________________________                                    

Due to their activities described above, the compounds of formula I are useful as anti-inflammatory and anti-allergic medicaments for larger mammals, in particular humans, for treating inflammatory and allergic diseases. The orally active compounds of the invention may act in several ways, since they are active against several of the principal mediators implicated in inflammatory processes and asthmatic complaints. As a result of this activity profile it can be assumed that in the treatment of allergy-based and non-allergy-based asthma symptoms, the compounds of the invention will not only alleviate the symptomatic complaints associated with asthmatic diseases, but also may reduce the associated inflammation.

The doses to be used may vary from individual to individual and of course will vary depending on the nature of the condition to be treated, the substance used, and the manner of administration. For example, parenteral formulations will generally contain less active substance than oral preparations. However, medicament forms having an active ingredient content of 10 to 250 mg per individual dose are generally suitable for administration to larger mammals, in particular humans.

As medicaments, the compounds of formula I may be contained with conventional pharmaceutical auxiliaries in galenic formulations such as, for example, tablets, capsules, suppositories, or solutions. These galenic formulations may be produced by known methods using conventional solid carriers such as, for example, lactose, starch or talcum, or liquid paraffins, and using conventional pharmaceutical auxiliaries, for example, tablet disintegrating agents, solubility promoters or preservatives.

The following examples are intended to illustrate the invention in further detail without limiting its scope.

EXAMPLE 1 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one

A) 45.3 g (=0.23 m) of 6-bromocaproic acid were treated with 63.6 g (=0.235 m) of phosphorus tribromide with stirring, and then 75.1 g (=0.047 m) of bromine were added, the first half being added dropwise and the remainder more rapidly. The mixture was then heated at a temperature of 85°-90° C. and maintained at this temperature for 1.5 hours. A further 18.4 g (=0.115 m) of bromine were added at this temperature, and the reaction mixture was maintained at a temperature of 85°-90° C. for a further 18 hours. The reaction mixture was worked up by cooling it to 20° C. and adding it to a mixture of 700 ml cooled water and 500 ml of cold hexane. The organic phase was separated, and the aqueous phase was washed two more times with 100 ml of hexane each time. The organic phases were combined and dried over sodium sulfate. The solvent was then distilled off. The 2,6-dibromocaproic acid bromide which remained as an oily residue was characterized by IR and NMR spectroscopy and further processed without additional purification.

B) 9.25 g (=0.07 m) of 2-aminothiophenol, 27.9 g of benzyltrimethylammonium chloride, and 25 g of sodium hydrogen carbonate were introduced into 150 ml of chloroform with stirring. The resulting suspension was cooled to -5° C., and a solution of 25.3 g of 2,6-dibromocaproic acid bromide in 70 ml of chloroform was added slowly with stirring to the cooled suspension. The addition took 30 minutes, and the temperature varied between -5° C. and +5° C. The mixture was maintained in this temperature range for a further hour. The mixture was then heated under reflux for 7 hours. Afterward it was cooled, filtered and the chloroform was distilled off from the filtrate. The remaining residue was treated with water and toluene. The organic phase was separated, dried, and fractionated by column chromatography. The fraction containing 2-(4-bromobutyl)-2H-1,4-benzothiazine-3(4H)-one was separated. After crystallization in the presence of diethyl ether, 5.9 g of 2 -(4-bromobutyl)-2H-1,4-benzothiazine-3(4H)-one were obtained from this fraction as slightly beige-colored crystals having a melting point of 100° C.

C) A mixture of 3.6 g (=0.012 m) of 2-(4-bromobutyl)-2H-1,4-benzothiazine-3(4H)-one, 2.12 g (=0.012 m) of N-(4-methylpyridin-2-yl)-piperazine, and 1.83 g (=0.018 m) of triethylamine in 100 ml of toluene was heated at reflux for 9 hours with stirring, during which a further 0.46 g of triethylamine was added after 3 hours, and again a further 0.9 g of triethylamine was added after 6 hours.

The reaction mixture was worked up by cooling it to 20° C. and adding 200 ml of water. The organic phase was separated, and the toluene was distilled off. The remaining residue was dissolved in 50 ml of 20% strength aqueous hydrochloric acid solution, and the solution was washed with toluene. The aqueous phase was made alkaline to pH 9 and then extracted with dichloromethane. The dichloromethane extract was washed, dried over calcium chloride, and the dichloromethane was distilled off. The crude title compound which remained as a residue was purified by column chromatography and then recrystallized from a 50/50 v/v mixture of toluene and isopropanol. 2.4 g of 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one were obtained as colorless crystals having a melting point of 119° C.

EXAMPLE 2 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4 -benzothiazine-3(4H) -thione

5.95 g (=0.015 m) of 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3 (4H) -one prepared according to Example 1 were dissolved in 60 ml of xylene at a temperature of 60° C. 6.9 g of P₄ S₁₀ were added to the solution, and the reaction mixture was heated at reflux for 1 hour with stirring.

The reaction mixture was cooled, and the resulting precipitate was separated and added to a mixture of 160 ml of 2N aqueous sodium hydroxide solution and 200 ml of dichloromethane. Further addition of 50 ml of water and 50 ml of dichloromethane yielded a reaction solution with a slight precipitate, which was removed by filtration. The organic phase then was separated, dried, and the solvent was distilled off. 5.2 g of a residue were obtained and fractionated by column chromatography. The title compound was crystallized from the fraction which contained it in a 50/50 v/v mixture of diethyl ether and ethyl acetate. 3.1 g of 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-thione were obtained in the form of beige-colored crystals having a melting point of 119° C.

EXAMPLE 3 4-methyl-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one

2 g (=0.005 m) of 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one prepared according to Example 1 were dissolved in 20 ml of anhydrous dimethylformamide with stirring. 0.151 g of sodium hydride were added under a nitrogen atmosphere, and the resulting suspension was maintained at room temperature for 10 minutes. 0.86 g of methyl iodide was then added all at once, and the reaction mixture was stirred for 2.5 hours at room temperature. The reaction mixture was worked up by distilling off the solvent, adding 100 ml of water to the residue, and extracting the mixture with 100 ml of ethyl acetate. The organic phase was concentrated by evaporating the solvent, and the crude title compound which remained as a residue was purified by column chromatography. The resulting base was dissolved in isopropanolic 2.3N hydrochloric acid. The hydrochloride of the title compound which precipitated as a white precipitate was filtered out. 0.7 g of 4 -methyl-2-{4-[4-(4methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one dihydrochloride having the empirical formula C₂₃ H₃₀ N₄ OS, 2HCl, 2.5 H₂ O and a melting point of 163° C. were obtained.

EXAMPLE 4 4-methyl-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one

A) 0.1 mole of 2-aminobenzothiazole and 0.1 mole of methyl iodide were heated under reflux in 50 ml of absolute ethanol for 12-15 hours. The 2-imino-3-methylbenzothiazole hydroiodide which precipitated was separated and dissolved in hot water. The solution was rendered alkaline by adding a saturated aqueous sodium carbonate solution. The 2-imino-3-methylbenzothiazole which precipitated was separated, washed with water and dried under reduced pressure.

B) The product obtained above was heated under reflux for 36 hours in 50% strength potassium hydroxide solution. The solution was worked up by diluting it with water and adjusted to pH 6 by adding aqueous 5N acetic acid solution. The aqueous solution was then extracted several times with ethyl acetate. The solvent was distilled off from the combined organic phases under reduced pressure. The 2-(methylamino)-thiophenol which remained as a residue was used in the subsequent reaction step without further purification.

C) 4.5 g (=0.032 m) of 2-(methylamino)-thiophenol, 6 g of triethylbenzylammonium chloride, and 11.20 g of sodium hydrogen carbonate were added to 120 ml of chloroform. The resulting suspension was cooled to 5° C., and then a solution of 10.88 g of 2,6-dibromohexanoyl bromide in 20 ml of chloroform was added dropwise so slowly that the temperature did not exceed 5° C. 20 minutes were required for the addition. The reaction mixture was then allowed to warm to room temperature and was subsequently heated under reflux for 4 hours. The reaction mixture was worked up by cooling and filtering it. The chloroform phase was washed, dried over sodium sulfate, and the solvent was distilled off. The 2-(4-bromobutyl)-4-methyl-2H-1,4-benzothiazine-3(4H)-one which formed was isolated from the remaining residue by fractional column chromatography. 2.78 g of white crystals having a melting point of 116° C. were obtained.

D) The product obtained above was reacted analogously to Example 1 C) with N-(4-methylpyridin-2-yl)-piperazine in toluene with addition of triethylamine. The resulting 4-methyl-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one was converted as described in Example 3 to the corresponding dihydrochloride having the empirical formula C₂₃ H₃₀ N₄ OS, 2HCl, 2.5 H₂ O and a melting point of 163° C.

EXAMPLE 5 2-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-2H-1,4-benzothiazine-3(4H)-one

A) 0.8 ml (=1 equivalent) of sulfonyl chloride was added dropwise with stirring at room temperature to a suspension of 10.0 mmoles of 2H-1,4-benzothiazine-3(4H)-one in 10 ml of dichloromethane, and the reaction mixture was stirred for a further 5 hours at room temperature. The mixture was worked up by evaporating it to dryness under reduced pressure. The 2-chloro-2H-1,4-benzothiazine-3(4H)-one which remained as a residue (melting point 189°-210° C. with decomposition) was processed further in the next step without additional purification.

B) 7 g (=0.035 m) of 2-chloro-2H-1,4-benzothiazine-3(4H)-one, 6.2 g of N-(4-methylpyridin-2-yl)-piperazine, and 7 g of triethylamine were heated at reflux with stirring for 5 hours in 100 ml of toluene. The suspension was worked up by diluting it with 200 ml of toluene, and the resulting precipitate was filtered out and dissolved in 20% strength aqueous hydrochloric acid solution. The solution was rendered alkaline by adding an ammonium hydroxide solution, and the resulting precipitate was filtered out, washed with water and dried. 2 g of beige-colored crystalline 2-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-2H-1,4-benzothiazine-3(4H)-one having a melting point of 245° C. were obtained.

EXAMPLE 6 7-hydroxy-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one

360 mg of 7-methoxy-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one (see Example 19) prepared analogously to Example 1 were added to 5 ml of dichloromethane with exclusion of moisture. After cooling to -5° C., a solution of 0.73 g of boron tribromide in 1 ml of methylene chloride was added dropwise with stirring. Stirring was then continued for a further 30 minutes at room temperature. The reaction mixture was worked up by adding it with stirring to a mixture of ice and aqueous sodium hydrogen carbonate solution. 200 ml of chloroform were then added. The resulting organic solution was washed with water, dried over sodium sulfate, filtered and concentrated under reduced pressure. The title compound was obtained from the remaining residue by fractional column chromatography. The fractions containing the title compound were concentrated and treated with ether. 30 mg of 7-hydroxy-2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]butyl}-2H-1,4-benzothiazine-3(4H)-one were obtained as white crystals having a melting point of 212° C.

The compounds of formula I listed in the following Table I were also obtained following the procedures described in the foregoing examples.

                                      TABLE I                                      __________________________________________________________________________     Ex.                                                                               R.sup.1                                                                           R.sup.2                                                                              R.sup.3                                                                            X Y n R.sup.4  Salt form                                                                           M.p. in °C.                         __________________________________________________________________________      7 H  H     H   O O 4 4-CH.sub.3 -pyrid-2-                                                                    2.HCl                                                                               180 (D)                                     8 H  H     H   S O 3 4-CH.sub.3 -pyrid-2-                                                                    Base 140                                         9 H  H     H   O O 3 4-CH.sub.3 -pyrid-2-                                                                    2.HCl                                                                               183                                        10 H  H     7-CH.sub.3                                                                         S O 3 4-CH.sub.3 -pyrid-2-                                                                    2.HCl                                                                               126                                        11 H  H     H   S S 3 4-CH.sub.3 -pyrid-2-                                                                    Base 134                                        12 H  H     H   S O 4 pyrim-2- Base 140                                        13 H  H     H   S O 4 5-CH.sub.3 -pyrid-2-                                                                    Base 128                                        14 H  H     H   O S 3 4-CH.sub.3 -pyrid-2-                                                                    2.HCl                                                                               170                                        15 H  H     H   S O 3 5-cl-pyrid-2-                                                                           Base 153                                        16 H  H     H   S O 4 6-CH.sub.3 O-pyrid-2-                                                                   Base 132                                        17 H  H     H   S O 4 pyrid-2- Base 125                                        18 H  7-F-- H   S O 4 4-CH.sub.3 -pyrid-2-                                                                    HCl  162                                        19 H  7-CH.sub.3 O--                                                                       H   S O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 123                                        20 H  7-Cl--                                                                               H   S O 4 6-CH.sub.3 -pyrid-2-                                                                    Base  92                                        21 H  6-CH.sub.3 --                                                                        7-CH.sub.3                                                                         S O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 114                                        22 H  6-CH.sub.3 --                                                                        H   O O 3 4-CH.sub.3 -pyrid-2-                                                                    Base 115                                        23 H  6-Cl--                                                                               H   O O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 116                                        24 H  6-CH.sub.3 --                                                                        H   O O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 126                                        25 H  7-HO--                                                                               H   S O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 126                                        26 H  H     H   S O 4 3-CH.sub.3 -pyrid-2-                                                                    Base 119                                        27 H  7-Cl  H   S O 4 4-CH.sub.3 -pyrid-2-                                                                    Base 152                                        28 n- H     H   S O 4 4-CH.sub.3 -pyrid-2-                                                                    3.HCl                                                                               148                                           C.sub.4 H.sub.9                                                             __________________________________________________________________________      pyrid-2- = pyridin2-yl,                                                        Base = free base,                                                              D = decomposition                                                              pyrim2- = pyrimidin2-yl                                                        HCl = hydrochloride,                                                     

EXAMPLE I Tablets containing 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one

Tablets were produced having the following composition per tablet:

    ______________________________________                                         2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-                                                            20 mg                                                  yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one                                      Corn starch             60 mg                                                  Lactose                 135 mg                                                 Gelatine (10% strength solution)                                                                        6 mg                                                  ______________________________________                                    

The active ingredient, the corn starch and the lactose were mixed with the 10% strength gelatine solution to form a paste. The paste was comminuted and the resulting granules were placed on a suitable plate and dried at 45° C. The dried granules were passed through a comminuting machine and mixed with the following further adjuvants in a mixer:

    ______________________________________                                         Talcum            5 mg                                                         Magnesium stearate                                                                               5 mg                                                         Corn starch       9 mg                                                         ______________________________________                                    

and then pressed to form 240 mg tablets.

The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations falling within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. A compound corresponding to the formula I ##STR28## wherein X denotes oxygen or sulfur,Y denotes oxygen or sulfur, R¹ denotes hydrogen or lower alkyl, R² denotes hydrogen, lower alkyl, halogen, lower alkoxy, hydroxy, nitro or trifluoromethyl, and R³ denotes hydrogen, lower alkyl, halogen or lower alkoxy, or R² and R³ are bonded to adjacent carbon atoms and together denote an alkylenedioxy group having 1-2 carbon atoms, n is an integer from 0 to 4, and R⁴ is a 6-membered unsaturated heterocycle containing 1 or 2 nitrogen atoms not directly bonded to the piperazine ring, said heterocycle being substituted by 0 to 2 substituents bonded to carbon atoms selected from the group consisting of lower alkyl, lower alkoxy and halogen,and physiologically acceptable acid addition salts thereof.
 2. A compound according to claim 1, wherein Y denotes oxygen.
 3. A compound according to claim 1, wherein n is 3 or
 4. 4. A compound according to claim 1, wherein R⁴ is an optionally substituted pyridyl group.
 5. A compound according to claim 4, wherein R⁴ is a 4-(lower alkyl)-pyrid-2-yl group.
 6. A compound according to claim 1, wherein R¹ denotes hydrogen.
 7. A compound according to claim 1, wherein R² denotes hydrogen or lower alkyl, and R³ denotes hydrogen.
 8. A compound according to claim 1, wherein Y denotes oxygen, R¹ denotes hydrogen, R² denotes hydrogen or lower alkyl, R³ denotes hydrogen, n is 3 or 4, and R⁴ denotes a pyridyl group optionally substituted by lower alkyl.
 9. 2-{4-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-butyl}-2H-1,4-benzothiazine-3(4H)-one according to claim 8, and physiologically acceptable acid addition salts thereof.
 10. A pharmaceutical composition comprising an effective anti-inflammatory or anti-allergic amount of a compound according to claim 1 and at least one conventional pharmaceutical adjuvant.
 11. A compound corresponding to the formula IV ##STR29## wherein X denotes oxygen or sulfur,R¹ denotes hydrogen or lower alkyl, R^(2') denotes hydrogen, lower alkyl, halogen, lower alkoxy, nitro or trifluoromethyl, and R³ denotes hydrogen, lower alkyl, halogen or lower alkoxy, or R^(2') and R³ are bonded to adjacent carbon atoms and together denote an alkylenedioxy group having 1-2 carbon atoms, and n is an integer from 0 to
 4. 